Risk diversification through multiple group membership in microfinance

We consider group formation in the joint liability setting in microfinance. Joint liability imposes additional liability of having to repay for group partners should they fail to repay. Multiple group membership allows diversification of that risk, and therefore, is welfare enhancing for risk averse agents. Welfare enhancement occurs even when the total loan of an agent is unchanged. Therefore, multiple borrowing is not synonymous with over-borrowing.